1. Field of the Invention
The present invention relates to a press apparatus suitable for manufacturing small-size precision parts such as electronic parts.
2. Description of the Prior Art
One press apparatus of this type has been known, which employs an arrangement in which a crank shaft and a side post are connected to each other through a connecting rod and the rotary motion of the crank shaft is converted into the vertical motion of the slide post, that is, a so-called crank mechanism, thereby moving a slide which is fixed to the lower end of the slide post in the vertical direction.
Conventional apparatus having this type of crank mechanism necessitate provision of bearings which are disposed at the connection between the connecting rod and the crank shaft and at the connection between the connecting rod and the slide post. However, the performance of this apparatus is not satisfactory in the manufacture of small-size precision parts which must be worked with a high-degree of accuracy because these bearing portions tend to generate certain amount of play and because the vertical reciprocating motion of the slide post generated by the crank mechanism cannot be obtained as a movement representative of a perfect sine curve.